Furfuryl alcohol-assisted deep eutectic solvent-derived Fe-doped porous carbon: a robust magnetically separable catalyst for dye degradation via a Fenton-like reaction

Abstract

This study introduces a facile pathway to synthesize Fe-doped porous activated carbons (Fe-pACs) through pyrolysis of a homogenous mixture of in situ formed poly(furfuryl alcohol) (PFA) in an iron(III) chloride-based deep eutectic solvent (DES). Crosslinking polymerization of furfuryl alcohol (FA) into PFA, incorporating DES molecules, and their subsequent heat treatment resulted in highly porous structured carbon materials. TGA analysis revealed that the weight ratio-based incorporation of DES and FA significantly increased the thermal stability of the ensuing polymerized mixture, which in turn could have restricted pore collapse during the pyrolysis process, resulting in the highest surface area of 204 m² g⁻¹. Fe-pACs exhibited promising activity, achieving 99% degradation efficiency of methylene blue (MB) dye within 30 min via a Fenton-like reaction under optimized reaction conditions (pH 4.5, 100 ppm MB solution, 2 mM of H₂O₂, and 0.2 g L⁻¹ catalyst). The effect of various reaction parameters, such as reaction temperature, pH, amount of catalyst and oxidant, and dye concentration, were also investigated. The dye degradation reaction was found to follow the second-order kinetics. Moreover, the recyclability results validated the stability of the Fe-pACs under the described reaction conditions, showing significant activity even after five consecutive cycles.